From 35aaa33ac4a6c6493a459e5e606690272f5c1aa2 Mon Sep 17 00:00:00 2001
From: David Vulakh <33737747+dvulakh@users.noreply.github.com>
Date: Tue, 14 Jan 2025 15:24:16 -0500
Subject: [PATCH] Erase `global_` by moving the modality to a `[@globalized]`
 attribute (#93)

---
 lib/Normalize_std_ast.ml               | 39 ++++++++++++++++++++++++++
 test/passing/tests/local_erased.ml.ref |  7 +++--
 test/passing/tests/modes-erased.ml.ref | 12 +++++---
 vendor/parser-extended/parser.mly      | 18 +++++++++---
 vendor/parser-standard/ast_mapper.ml   |  5 +++-
 5 files changed, 70 insertions(+), 11 deletions(-)

diff --git a/lib/Normalize_std_ast.ml b/lib/Normalize_std_ast.ml
index 4c75ba89d3..a418272643 100644
--- a/lib/Normalize_std_ast.ml
+++ b/lib/Normalize_std_ast.ml
@@ -16,6 +16,11 @@ let is_doc = function
   | {attr_name= {Location.txt= "ocaml.doc" | "ocaml.text"; _}; _} -> true
   | _ -> false
 
+let globalized_attr =
+  Ast_helper.Attr.mk ~loc:Location.none
+    (Location.mknoloc "globalized")
+    (PStr [])
+
 (* We rewrite both "[@immediate]" and "[@ocaml.immediate]" into ":
    immediate", which is then turned into just "[@immediate]" if we are
    erasing jane syntax. This means "[@ocaml.immediate]" get rewritten to
@@ -478,6 +483,38 @@ let make_mapper conf ~ignore_doc_comments ~erase_jane_syntax =
       else ext )
     |> Ast_mapper.default_mapper.extension_constructor m
   in
+  let label_declaration (m : Ast_mapper.mapper) ld =
+    (* CR modes: Develop a more general mechanism for "erasing" modalities
+       into attributes *)
+    let global__ =
+      List.exists ld.pld_modalities ~f:(function
+        | {Location.txt= Modality "global"; _} -> true
+        | {txt= Modality _; _} -> false )
+    in
+    let ld = Ast_mapper.default_mapper.label_declaration m ld in
+    { ld with
+      pld_attributes=
+        ( if erase_jane_syntax && global__ then
+            globalized_attr :: ld.pld_attributes
+          else ld.pld_attributes ) }
+  in
+  let constructor_argument (m : Ast_mapper.mapper) ca =
+    (* CR modes: Develop a more general mechanism for "erasing" modalities
+       into attributes *)
+    let global__ =
+      List.exists ca.pca_modalities ~f:(function
+        | {Location.txt= Modality "global"; _} -> true
+        | {txt= Modality _; _} -> false )
+    in
+    let ca = Ast_mapper.default_mapper.constructor_argument m ca in
+    { ca with
+      pca_type=
+        ( if erase_jane_syntax && global__ then
+            { ca.pca_type with
+              ptyp_attributes= globalized_attr :: ca.pca_type.ptyp_attributes
+            }
+          else ca.pca_type ) }
+  in
   { Ast_mapper.default_mapper with
     location
   ; attribute
@@ -486,10 +523,12 @@ let make_mapper conf ~ignore_doc_comments ~erase_jane_syntax =
   ; signature
   ; class_signature
   ; class_structure
+  ; constructor_argument
   ; expr
   ; pat
   ; typ
   ; type_declaration
+  ; label_declaration
   ; modes
   ; modalities
   ; value_binding
diff --git a/test/passing/tests/local_erased.ml.ref b/test/passing/tests/local_erased.ml.ref
index 17589bcb83..90294edb91 100644
--- a/test/passing/tests/local_erased.ml.ref
+++ b/test/passing/tests/local_erased.ml.ref
@@ -29,9 +29,12 @@ let f () =
   let () = g (fun () -> ()) in
   "asdfasdfasdfasdfasdfasdfasdf"
 
-type 'a r = {mutable a: 'a; b: 'a; c: 'a}
+type 'a r = {mutable a: 'a; b: 'a; c: 'a [@globalized]}
 
-type 'a r = Foo of 'a | Bar of 'a * 'a | Baz of int * string * 'a
+type 'a r =
+  | Foo of ('a[@globalized])
+  | Bar of 'a * ('a[@globalized])
+  | Baz of (int[@globalized]) * string * ('a[@globalized])
 
 type ('a, 'b) cfn = a:'a -> ?b:b -> 'a -> int -> 'b
 
diff --git a/test/passing/tests/modes-erased.ml.ref b/test/passing/tests/modes-erased.ml.ref
index f77b1a74e4..5b5328aeaa 100644
--- a/test/passing/tests/modes-erased.ml.ref
+++ b/test/passing/tests/modes-erased.ml.ref
@@ -370,15 +370,19 @@ module Interaction_with_existing_syntax = struct
 
   (* modalities on record fields *)
 
-  type t = {x: t}
+  type t = {x: t [@globalized]}
 
-  type t = A of {x: t}
+  type t = A of {x: t [@globalized]}
 
   (* modalities on constructor arguments *)
 
-  type t = A of typ | B of typ1 * typ2
+  type t =
+    | A of (typ[@globalized])
+    | B of (typ1[@globalized]) * (typ2[@globalized])
 
-  type t = A : typ -> t | B : typ1 * typ2 -> t
+  type t =
+    | A : (typ[@globalized]) -> t
+    | B : (typ1[@globalized]) * (typ2[@globalized]) -> t
 end
 
 module Regressions = struct
diff --git a/vendor/parser-extended/parser.mly b/vendor/parser-extended/parser.mly
index 8de04b7514..93bc3a414b 100644
--- a/vendor/parser-extended/parser.mly
+++ b/vendor/parser-extended/parser.mly
@@ -280,9 +280,15 @@ let global_loc = mknoloc "extension.global"
 let global_attr =
   Attr.mk ~loc:Location.none (global_loc) (PStr [])
 
+let globalized_attr = Attr.mk ~loc:Location.none (mknoloc "globalized") (PStr [])
+
 let mkld_global ld =
-  if Erase_jane_syntax.should_erase () then ld else
-  { ld with pld_attributes = global_attr :: ld.pld_attributes }
+  let attr =
+    if Erase_jane_syntax.should_erase ()
+    then globalized_attr
+    else global_attr
+  in
+  { ld with pld_attributes = attr :: ld.pld_attributes }
 
 let mkld_global_maybe gbl ld =
   match gbl with
@@ -290,8 +296,12 @@ let mkld_global_maybe gbl ld =
   | Nothing -> ld
 
 let mkcty_global cty =
-  if Erase_jane_syntax.should_erase () then cty else
-  { cty with ptyp_attributes = global_attr :: cty.ptyp_attributes }
+  let attr =
+    if Erase_jane_syntax.should_erase ()
+    then globalized_attr
+    else global_attr
+  in
+  { cty with ptyp_attributes = attr :: cty.ptyp_attributes }
 
 let mkcty_global_maybe gbl cty =
   match gbl with
diff --git a/vendor/parser-standard/ast_mapper.ml b/vendor/parser-standard/ast_mapper.ml
index 4bc69554ee..a58f1d2680 100644
--- a/vendor/parser-standard/ast_mapper.ml
+++ b/vendor/parser-standard/ast_mapper.ml
@@ -50,6 +50,7 @@ type mapper = {
   constant: mapper -> constant -> constant;
   constructor_declaration: mapper -> constructor_declaration
                            -> constructor_declaration;
+  constructor_argument: mapper -> constructor_argument -> constructor_argument;
   directive_argument: mapper -> directive_argument -> directive_argument;
   expr: mapper -> expression -> expression;
   extension: mapper -> extension -> extension;
@@ -234,7 +235,7 @@ module T = struct
     { pca_type; pca_loc; pca_modalities }
 
   let map_constructor_arguments sub = function
-    | Pcstr_tuple l -> Pcstr_tuple (List.map (map_constructor_argument sub) l)
+    | Pcstr_tuple l -> Pcstr_tuple (List.map (sub.constructor_argument sub) l)
     | Pcstr_record l ->
         Pcstr_record (List.map (sub.label_declaration sub) l)
 
@@ -896,6 +897,8 @@ let default_mapper =
           ~info:Docstrings.empty_info
       );
 
+    constructor_argument = T.map_constructor_argument;
+
     label_declaration =
       (fun this {pld_name; pld_type; pld_loc; pld_mutable; pld_modalities; pld_attributes} ->
          Type.field